Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 101
Filtrar
1.
Open Biol ; 14(3): 230440, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38442865

RESUMO

Microtubule organization and reorganization during the cell cycle are achieved by regulation of the number, distribution and activity of microtubule-organizing centres (MTOCs). In fission yeast, the Mto1/2 complex determines the activity and distribution of cytoplasmic MTOCs. Upon mitosis, cytoplasmic microtubule nucleation ceases; inactivation of the Mto1/2 complex is triggered by Mto2 hyperphosphorylation. However, the protein kinase(s) that phosphorylates Mto2 remains elusive. Here we show that a conserved signalling network, called MOR (morphogenesis Orb6 network) in fission yeast, negatively regulates cytoplasmic MTOCs through Mto2 phosphorylation to ensure proper microtubule organization. Inactivation of Orb6 kinase, the most downstream MOR component, by attenuation of MOR signalling leads to reduced Mto2 phosphorylation, coincident with increased number of both Mto2 puncta and cytoplasmic microtubules. These defects cause the emergence of uncoordinated mitotic cells with cytoplasmic microtubules, resulting in reduced spindle assembly. Thus, the regulation of Mto2 by the MOR is crucial for cytoplasmic microtubule organization and contributes to reorganization of the microtubule cytoskeletons during the cell cycle.


Assuntos
Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Ciclo Celular , Mitose , Fosforilação , Microtúbulos , Proteínas Serina-Treonina Quinases , Proteínas de Ciclo Celular , Proteínas de Schizosaccharomyces pombe/genética
2.
Radiat Oncol ; 19(1): 32, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38459580

RESUMO

BACKGROUND: Centrally located lung tumours present a challenge because of their tendency to exhibit symptoms such as airway obstruction, atelectasis, and bleeding. Surgical resection of these tumours often requires sacrificing the lungs, making definitive radiotherapy the preferred alternative to avoid pneumonectomy. However, the proximity of these tumours to mediastinal organs at risk increases the potential for severe adverse events. To mitigate this risk, we propose a dual-method approach: deep inspiration breath-hold (DIBH) radiotherapy combined with adaptive radiotherapy. The aim of this single-centre, single-arm phase II study is to investigate the efficacy and safety of DIBH daily online adaptive radiotherapy. METHODS: Patients diagnosed with centrally located lung tumours according to the International Association for the Study of Lung Cancer recommendations, are enrolled and subjected to DIBH daily online adaptive radiotherapy. The primary endpoint is the one-year cumulative incidence of grade 3 or more severe adverse events, as classified by the Common Terminology Criteria for Adverse Events (CTCAE v5.0). DISCUSSION: Delivering definitive radiotherapy for centrally located lung tumours presents a dilemma between ensuring optimal dose coverage for the planning target volume and the associated increased risk of adverse events. DIBH provides measurable dosimetric benefits by increasing the normal lung volume and distancing the tumour from critical mediastinal organs at risk, leading to reduced toxicity. DIBH adaptive radiotherapy has been proposed as an adjunct treatment option for abdominal and pelvic cancers. If the application of DIBH adaptive radiotherapy to centrally located lung tumours proves successful, this approach could shape future phase III trials and offer novel perspectives in lung tumour radiotherapy. TRIAL REGISTRATION: Registered at the Japan Registry of Clinical Trials (jRCT; https://jrct.niph.go.jp/ ); registration number: jRCT1052230085 ( https://jrct.niph.go.jp/en-latest-detail/jRCT1052230085 ).


Assuntos
Coração , Neoplasias Pulmonares , Humanos , Suspensão da Respiração , Órgãos em Risco , Neoplasias Pulmonares/radioterapia , Pulmão , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Ensaios Clínicos Fase II como Assunto
3.
J Appl Clin Med Phys ; : e14307, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38363044

RESUMO

BACKGROUND: For patient-specific quality assurance (PSQA) for small targets, the dose resolution can change depending on the characteristics of the dose calculation algorithms. PURPOSE: This study aimed to evaluate the influence of the dose calculation algorithms Acuros XB (AXB), anisotropic analytical algorithm (AAA), photon Monte Carlo (pMC), and collapsed cone (CC) on a helical diode array using volumetric-modulated arc therapy (VMAT) for small targets. MATERIALS AND METHODS: ArcCHECK detectors were inserted with a physical depth of 2.9 cm from the surface. To evaluate the influence of the dose calculation algorithms for small targets, rectangular fields of 2×100, 5×100, 10×100, 20×100, 50×100, and 100×100 mm2 were irradiated and measured using ArcCHECK with TrueBeam STx. A total of 20 VMAT plans for small targets, including the clinical sites of 19 brain metastases and one spine, were also evaluated. The gamma passing rates (GPRs) were evaluated for the rectangular fields and the 20 VMAT plans using AXB, AAA, pMC, and CC. RESULTS: For rectangular fields of 2×100 and 5×100 mm2 , the GPR at 3%/2 mm of AXB was < 50% because AXB resulted in a coarser dose resolution with narrow beams. For field sizes > 10×100 mm2, the GPR at 3%/2 mm was > 88.1% and comparable for all dose calculation algorithms. For the 20 VMAT plans, the GPRs at 3%/2 mm were 79.1 ± 15.7%, 93.2 ± 5.8%, 94.9 ± 4.1%, and 94.5 ± 4.1% for AXB, AAA, pMC, and CC, respectively. CONCLUSION: The behavior of the dose distribution on the helical diode array differed depending on the dose calculation algorithm for small targets. Measurements using ArcCHECK for VMAT with small targets can have lower GPRs owing to the coarse dose resolution of AXB around the detector area.

4.
Ann Thorac Cardiovasc Surg ; 30(1)2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-37468261

RESUMO

PURPOSE: Saphenous vein grafts (SVGs) sometimes occur as vein graft stenosis or failure in coronary artery bypass grafting. The purpose of this study was to detect the factors affecting vein graft atherosclerosis. METHODS: We performed two analysis. In the first analysis, we enrolled 120 grafts using conventionally harvested saphenous vein graft (C-SVG) and followed-up with multiple coronary computed tomography angiography (CCTA). We examined the factors that contribute to the graft atherosclerosis defined by graft failure at subsequent CCTA or substantial progression of graft stenosis (a decrease of ≥0.6 mm in diameter). In the second analysis, 66 grafts using no-touch harvested saphenous vein graft (N-SVG) were compared with those in the first analysis using C-SVG, focusing on the differences in intraoperative factors using propensity score-matched analysis. RESULTS: In the first analysis, graft atherosclerosis+ group comprised 27 grafts, which had a larger SVG diameter, lower graft velocity, and higher graft/native ratio in diameter than the graft atherosclerosis- group. In the multivariable analysis, slow graft velocity and graft/native ≥2 in diameter were independently associated with the graft atherosclerosis. In the second analysis, the N-SVG group had a much greater graft velocity than the C-SVG group. CONCLUSION: Lower graft velocity and higher graft/native ratio in diameter were associated with the graft atherosclerosis. The N-SVG group had increased graft velocity, which may contribute to prevent the graft atherosclerosis.(Trial registration: UMIN Clinical Trial Registry no. UMIN000050482. Registered 3 March 2023, retrospectively registered.).


Assuntos
Aterosclerose , Veia Safena , Humanos , Aterosclerose/diagnóstico por imagem , Constrição Patológica , Angiografia Coronária , Ponte de Artéria Coronária/efeitos adversos , Ponte de Artéria Coronária/métodos , Seguimentos , Veia Safena/diagnóstico por imagem , Veia Safena/transplante , Resultado do Tratamento , Grau de Desobstrução Vascular
5.
Indian J Thorac Cardiovasc Surg ; 39(6): 570-576, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37885936

RESUMO

Purpose: Optimal strategy for transcatheter aortic valve implantation (TAVI) in patients with coronary artery disease (CAD) is unresolved. We evaluated the surgical outcomes of hybrid coronary artery bypass grafting (CABG) and TAVI in elderly patients. Methods: We retrospectively evaluated patients who underwent simultaneous TAVI and CABG at Wakayama Medical University, Japan. All patients underwent off-pump CABG (OPCAB) including minimally invasive cardiac surgery (MICS-CABG). In an earlier period, OPCAB + transfemoral TAVI (TF-TAVI) was the only method used, while in a later period, we introduced MICS-CABG and alternative approaches for TAVI. Results: Twenty-seven patients were enrolled, the average age was 83.6 ± 5.1 years. In the MICS-CABG and TAVI group, average patient age was higher (87.0 ± 3.1 years) than in the earlier group. Thirty-day and in-hospital mortalities were zero. Incomplete revascularization rate was 33.3% and one patient required percutaneous coronary intervention after the operation. Graft patency rate was 100%. In MICS-CABG group, the number of distal anastomoses was smaller (1.29, range 1-2), but the number of days required to re-starting walking and postoperative hospital stay were shorter, and the rate of discharge to home was higher (100%) than in the other groups. Conclusions: Although 33.3% of patients did not achieve complete revascularization, there was no 30-day or in-hospital mortality. TAVI and hybrid OPCAB, including MICS-CABG, were suggested to be feasible treatment in elderly patients.

6.
Genes Cells ; 28(12): 868-880, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37837427

RESUMO

Primary cilia on neural stem/progenitor cells (NSPCs) play an important role in determining cell fate, although the regulatory mechanisms involved in the ciliogenesis remain largely unknown. In this study, we analyzed the effect of the leukemia inhibitory factor (LIF) for the primary cilia in immortalized human NSPCs. LIF withdrawal elongated the primary cilia length, whereas the addition of LIF shortened it. Microarray gene expression analysis revealed that differentially expressed genes (DEGs) associated with LIF treatment were related with the multiple cytokine signaling pathways. Among the DEGs, C-C motif chemokine 2 (CCL2) had the highest ranking and its increase in the protein concentration in the NSPCs-conditioned medium after the LIF treatment was confirmed by ELISA. Interestingly, we found that CCL2 was a negative regulator of cilium length, and LIF-induced shortening of primary cilia was antagonized by CCL2-specific antibody, suggesting that LIF could influence cilia length via upregulating CCL2. The shortening effect of LIF and CCL2 on primary cilia was also observed in SH-SY5Y cells. The results of the study suggested that the LIF-CCL2 axis may well be a regulator of NSPCs and its primary cilia length, which could affect multiple cellular processes, including NSPC proliferation and differentiation.


Assuntos
Células-Tronco Neurais , Neuroblastoma , Humanos , Cílios/metabolismo , Transdução de Sinais , Fator Inibidor de Leucemia/genética , Fator Inibidor de Leucemia/metabolismo , Fator Inibidor de Leucemia/farmacologia , Células-Tronco Neurais/metabolismo , Diferenciação Celular/fisiologia
7.
Genes Cells ; 28(11): 811-820, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37723847

RESUMO

Autosomal dominant polycystic kidney disease (ADPKD) is a renal disorder caused by mutations in the PKD2 gene, which encodes polycystin-2/Pkd2, a transient receptor potential channel. The precise role of Pkd2 in cyst formation remains unclear. The fission yeast Schizosaccharomyces pombe has a putative transient receptor potential channel, Pkd2, which shares similarities with human Pkd2. In this study, truncation analyses of fission yeast Pkd2 were conducted to investigate its localization and function. The results revealed that Pkd2 localizes not only to the plasma membrane but also to the endoplasmic reticulum (ER) in fission yeast. Furthermore, Pkd2 regulates calcium signaling in fission yeast, with the transmembrane domains of Pkd2 being sufficient for these processes. Specifically, the C-terminal region of Pkd2 plays a crucial role in the regulation of calcium signaling. Interestingly, human Pkd2 also localized to the ER and had some impact on calcium signaling in fission yeast. However, human Pkd2 failed to suppress the loss of fission yeast Pkd2. These findings indicate that hPkd2 may not completely substitute for cellular physiology of fission yeast Pkd2. This study provides insights into the localization and functional characteristics of Pkd2 in fission yeast, contributing to our understanding of the pathogenesis of ADPKD.


Assuntos
Rim Policístico Autossômico Dominante , Schizosaccharomyces , Canais de Potencial de Receptor Transitório , Humanos , Rim Policístico Autossômico Dominante/genética , Rim Policístico Autossômico Dominante/patologia , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Sinalização do Cálcio/genética , Mutação , Canais de Potencial de Receptor Transitório/genética , Canais de Potencial de Receptor Transitório/metabolismo , Retículo Endoplasmático/metabolismo
8.
Phys Med ; 113: 102664, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37573811

RESUMO

PURPOSE: To evaluate the applicability of TRS-483 output correction factors (CFs) for small-field output factors (OFs) using different multi-leaf collimators (MLC) and field-shaping types. METHODS: All measurements were performed on TrueBeam, TrueBeam STx, and Halcyon using 6 MV flattening filter-free energy. Four detectors, including CC01, CC04, microDiamond, and EDGE, were used. Nominal field sizes ranging from 1 × 1 to 4 × 4, and 10 × 10 cm2 were used to measure small-field OFs at source-to-axis distance of 100 cm with a 0° gantry angle in a 3D water phantom. Further, the field-shaping types were defined using jaw collimator or MLC (five different configurations). A field size of 10 × 10 cm2 was used as the reference for calculation of OFs obtained as ratio of detector readings (OFdet). The percentage difference and coefficient of variation of OFdet and OFdet corrected by applying CF were compared for each field size and configuration. RESULTS: For OFdet corrected by applying CF, the ranges of percentage difference and coefficient of variation in all configurations for ≥ 2 × 2 cm2 fields were reduced from 1.2-2.2 to 0.8-1.3 percentage points (%pt) and from 0.5-1.0 to 0.4-0.7%, respectively. For 1 × 1 cm2 field, the ranges of percentage difference and coefficient of variation were reduced from 3.3-5.7 to 1.2-2.2 %pt and from 2.2-3.7 to 0.8-1.1%, respectively. CONCLUSIONS: The CFs described in TRS-483 dosimetry protocol have broad applicability in reducing OF variations between detectors under different MLC and field-shaping types.


Assuntos
Fótons , Radiometria , Aceleradores de Partículas , Imagens de Fantasmas
9.
Radiol Phys Technol ; 16(3): 422-429, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37474738

RESUMO

This study aimed to assess the effectiveness of a new patient-setup procedure using surface-guided imaging during the coronavirus disease 2019 (COVID-19) pandemic for left-sided whole-breast irradiation with deep inspiration breath-hold. Two setup procedures were compared regarding patient positioning accuracy for the first 22 patients. The first was a traditional setup (T-setup) procedure that used a surface-guided system after patient setup with traditional skin marks and lasers. The second procedure involved a new setup (N-setup) that used only a surface-guided system. The positioning accuracy of the remaining 23 patients was assessed using a setup that combined marker reduction and the N-setup procedure. No significant difference was observed in positioning accuracy between the two setups. The positioning accuracy of the marker-reduction setup was within 3 mm in all directions. The N-setup procedure may be a useful strategy for preventing infection during or after the COVID-19 pandemic.


Assuntos
Neoplasias da Mama , COVID-19 , Radioterapia Guiada por Imagem , Humanos , Feminino , Pandemias/prevenção & controle , Tato , Planejamento da Radioterapia Assistida por Computador/métodos , Posicionamento do Paciente , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/radioterapia , Suspensão da Respiração , Radioterapia Guiada por Imagem/métodos , Dosagem Radioterapêutica
10.
Neuroscience ; 524: 256-268, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37315734

RESUMO

Syntaxin-binding protein 1 (STXBP1, also known as Munc18-1) regulates exocytosis as a chaperone protein of Syntaxin1A. The haploinsufficiency of STXBP1 causes early infantile-onset developmental and epileptic encephalopathy, known as STXBP1 encephalopathy. Previously, we reported impaired cellular localization of Syntaxin1A in induced pluripotent stem cell-derived neurons from an STXBP1 encephalopathy patient harboring a nonsense mutation. However, the molecular mechanism of abnormal Syntaxin1A localization in the haploinsufficiency of STXBP1 remains unknown. This study aimed to identify the novel interacting partner of STXBP1 involved in transporting Syntaxin1A to the plasma membrane. Affinity purification coupled with mass spectrometry analysis identified a motor protein Myosin Va as a potential binding partner of STXBP1. Co-immunoprecipitation analysis of the synaptosomal fraction from the mouse and tag-fused recombinant proteins revealed that the STXBP1 short splice variant (STXBP1S) interacted with Myosin Va in addition to Syntaxin1A. These proteins colocalized at the tip of the growth cone and axons in primary cultured hippocampal neurons. Furthermore, RNAi-mediated gene silencing in Neuro2a cells showed that STXBP1 and Myosin Va were required for membrane trafficking of Syntaxin1A. In conclusion, this study proposes a potential role of STXBP1 in the trafficking of the presynaptic protein Syntaxin1A to the plasma membrane in conjunction with Myosin Va.


Assuntos
Encefalopatias , Proteínas Munc18 , Animais , Camundongos , Encefalopatias/genética , Membrana Celular/metabolismo , Proteínas Munc18/genética , Proteínas Munc18/metabolismo , Neurônios/metabolismo , Interferência de RNA
11.
Phys Med ; 110: 102605, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37167776

RESUMO

PURPOSE: Quantifying intra-fractional six-degree-of-freedom (6DoF) residual errors or motion from approved patient setups is necessary for accurate beam delivery in spine stereotactic body radiotherapy. However, previously reported errors were not acquired during beam delivery. Therefore, we aimed to quantify the 6DoF residual errors and motions during arc beam delivery using a concurrent cone-beam computed tomography (CBCT) imaging technique, intra-irradiation CBCT. METHODS: Consecutive 15 patients, 19 plans for various treatment sites, and 199 CBCT images were analyzed. Pre-irradiation CBCT was performed to verify shifts from the initial patient setup using the ExacTrac system. During beam delivery by two or three co-planar full-arc rotations, CBCT imaging was performed concurrently. Subsequently, an intra-irradiation CBCT image was reconstructed. Pre- and intra-irradiation CBCT images were rigidly registered to a planning CT image based on the bone to quantify 6DoF residual errors. RESULTS: 6DoF residual errors quantified using pre- and intra-irradiation CBCTs were within 2.0 mm/2.0°, except for one measurement. The mean elapsed time (mean ± standard deviation [min:sec]) after pre-irradiation CBCT to the end of the last arc beam delivery was 6:08 ± 1:25 and 7:54 ± 2:14 for the 2- and 3-arc plans, respectively. Root mean squares of residual errors for several directions showed significant differences; however, they were within 1.0 mm/1.0°. Time-dependent analysis revealed that the residual errors tended to increase with elapsed time. CONCLUSION: The errors represent the optimal intra-fractional error compared with those acquired using the pre-, inter-beam, and post-6DoF image guidance and can be acquired within a standard treatment timeslot.


Assuntos
Radiocirurgia , Radioterapia Guiada por Imagem , Humanos , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Tomografia Computadorizada de Feixe Cônico/métodos , Radioterapia Guiada por Imagem/métodos , Movimento (Física) , Erros de Configuração em Radioterapia
12.
Indian J Thorac Cardiovasc Surg ; 39(3): 296-299, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37124590

RESUMO

A 62-year-old male was admitted to our hospital with worsening dyspnea. Chest X-ray revealed dextrocardia, and echocardiography revealed decreased right ventricular function, a severely dilated tricuspid annulus, a massive tricuspid, and trivial mitral regurgitation. Patch augmentation of the tricuspid leaflet with auto-pericardium and ring annuloplasty with a flat-type upside-down artificial ring to fit the dextrocardia heart was performed. Echocardiography 4 years after the operation showed trivial regurgitation. Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-023-01477-9.

13.
Mol Neurobiol ; 60(7): 3664-3677, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36918517

RESUMO

Dystrophin is the causative gene for Duchenne and Becker muscular dystrophy (DMD/BMD), and it produces full-length and short dystrophin, Dp427 and Dp71, respectively, in the brain. The existence of the different dystrophin molecular complexes has been known for a quarter century, so it is necessary to derive precise expression profiles of the molecular complexes in the brain to elucidate the mechanism of cognitive symptoms in DMD/BMD patients. In order to investigate the Dp71 expression profile in cerebellum, we employed Dp71-specific tag-insertion mice, which allowed for the specific detection of endogenous Dp71 in the immunohistochemical analysis and found its expressions in the glial cells, Bergmann glial (BG) cells, and astrocytes, whereas Dp427 was exclusively expressed in the inhibitory postsynapses within cerebellar Purkinje cells (PCs). Interestingly, we found different cell-type dependent dystrophin molecular complexes; i.e., glia-associated Dp71 was co-expressed with dystroglycan (DG) and dystrobrevinα, whereas synapse-associated Dp427 was co-expressed with DG and dystrobrevinß. Furthermore, we investigated the molecular relationship of Dp71 to the AQP4 water channel and the Kir4.1 potassium channel, and found biochemical associations of Dp71 with AQP4 and Kir4.1 in both the cerebellum and cerebrum. Immunohistochemical and cytochemical investigations revealed partial co-localizations of Dp71 with AQP4 and Kir4.1 in the glial cells, indicating Dp71 interactions with the channels in the BG cells and astrocytes. Taken together, different cell-types, glial cells and Purkinje neurons, in the cerebellum express different dystrophin molecular complexes, which may contribute to pathological and physiological processes through the regulation of the water/ion channel and inhibitory postsynapses.


Assuntos
Aquaporinas , Canais de Potássio Corretores do Fluxo de Internalização , Camundongos , Animais , Distrofina/metabolismo , Células de Purkinje/metabolismo , Sinapses/metabolismo , Cerebelo/metabolismo , Neuroglia/metabolismo , Aquaporinas/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo
14.
J Radiat Res ; 64(1): 180-185, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36214326

RESUMO

In this study, an independent dose verification plugin (DVP) using the Eclipse Scripting Application Programming Interface (ESAPI) for brachytherapy was developed. The DVP was based on the general 2D formalism reported in AAPM-TG43U1. The coordinate and orientation of each source position were extracted from the translation matrix acquired from the treatment planning system (TPS), and the distance between the source and verification point (r) was calculated. Moreover, the angles subtended by the center-tip and tip-tip of the hypothetical line source with respect to the verification point (θ and ß) were calculated. With r, θ, ß and the active length of the source acquired from the TPS, the geometry function was calculated. As the TPS calculated the radial dose function, g(r), and 2D anisotropy function, F(r,θ), by interpolating and extrapolating the corresponding table stored in the TPS, the DVP calculated g(r) and F(r,θ) independently from equations fitted with the Monte Carlo data. The relative deviation of the fitted g(r) and F(r,θ) for the GammaMed Plus HDR 192Ir source was 0.5% and 0.9%, respectively. The acceptance range of the relative dose difference was set to ±1.03% based on the relative deviation between the fitted functions and Monte Carlo data, and the linear error propagation law. For 64 verification points from sixteen plans, the mean of absolute values of the relative dose difference was 0.19%. The standard deviation (SD) of the relative dose difference was 0.17%. The DVP maximizes efficiency and minimizes human error for the brachytherapy plan check.


Assuntos
Braquiterapia , Radioisótopos de Irídio , Humanos , Dosagem Radioterapêutica , Braquiterapia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Método de Monte Carlo , Radiometria/métodos
15.
Med Phys ; 50(3): 1274-1289, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36583601

RESUMO

BACKGROUND: Small-field dosimetry is challenging for radiotherapy dosimetry because of the loss of lateral charged equilibrium, partial occlusion of the primary photon source by the collimating devices, perturbation effects caused by the detector materials and their design, and the detector size relative to the radiation field size, which leads to a volume averaging effect. Therefore, a suitable tool for small-field dosimetry requires high spatial resolution, tissue equivalence, angular independence, and energy and dose rate independence to achieve sufficient accuracy. Recently, with the increasing use of combinations of coplanar and non-coplanar beams for small-field dosimetry, there is a need to clarify angular dependence for dosimetry where the detector is oriented at various angles to the incident beam. However, the effect of angular dependence on small-field dosimetry with coplanar and non-coplanar beams has not been fully clarified. PURPOSE: This study clarified the effect of angular dependence on small-field dosimetry with coplanar and non-coplanar beams using various detectors. METHODS: Seven different detectors were used: CC01, RAZOR, RAZOR Nano, Pinpoint 3D, stereotactic field diode (SFD), microSilicon, and microDiamond. All measurements were taken using a TrueBeam STx with 6 MV and 10 MV flattening filter-free (FFF) energies using a water-equivalent spherical phantom with a source-to-axis distance of 100 cm. The detector was inserted in a perpendicular orientation, and the gantry was rotated at 15° increments from the incidence beam angle. A multi-leaf collimator (MLC) with four field sizes of 0.5 × 0.5, 1 × 1, 2 × 2, and 3 × 3 cm2 , and four couch angles from 0°, 30°, 60°, and 90° (coplanar and non-coplanar) were adopted. The angular dependence response (AR) was defined as the ratio of the detector response at a given irradiation gantry angle normalized to the detector response at 0°. The maximum AR differences were calculated between the maximum and minimum AR values for each detector, field size, energy, and couch angle. RESULTS: The maximum AR difference for the coplanar beam was within 3.3% for all conditions, excluding the maximum AR differences in 0.5 × 0.5 cm2 field for CC01 and RAZOR. The maximum AR difference for non-coplanar beams was within 2.5% for fields larger than 1 × 1 cm2 , excluding the maximum AR differences for RAZOR Nano, SFD, and microSilicon. The Pinpoint 3D demonstrated stable AR tendencies compared to other detectors. The maximum difference was within 2.0%, except for the 0.5 × 0.5 cm2 field and couch angle at 90°. The tendencies of AR values for each detector were similar when using different energies. CONCLUSION: This study clarified the inherent angular dependence of seven detectors that were suitable for small-field dosimetry. The Pinpoint 3D chamber had the smallest angular dependence of all detectors for the coplanar and non-coplanar beams. The findings of this study can contribute to the calculation of the AR correction factor, and it may be possible to adapt detectors with a large angular dependence on coplanar and non-coplanar beams. However, note that the gantry sag and detector-specific uncertainties increase as the field size decreases.


Assuntos
Fótons , Radiometria , Fótons/uso terapêutico , Aceleradores de Partículas , Imagens de Fantasmas , Incerteza
16.
Lasers Surg Med ; 54(8): 1167-1176, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35916125

RESUMO

OBJECTIVES: Hair loss, including alopecia, is a common dermatological issue worldwide. At present, the application of fractional carbon dioxide (CO2 ) laser in the treatment of alopecia has been documented; however, the results vary between reports. These varying results may be due to the limited knowledge of cellular action in laser-irradiated skin. The objective of this study was to investigate the molecular and cellular mechanisms of laser treatment under effective conditions for hair cycle initiation. METHODS: A fractional CO2 laser was applied and optimized to initiate the hair cycle in a mouse model of alopecia. Several cellular markers were analyzed in the irradiated skin using immunofluorescence staining. Cellular populations and their comprehensive gene expression were analyzed using single-cell RNA sequencing and bioinformatics. RESULTS: The effective irradiation condition for initiating the hair cycle was found to be 15 mJ energy/spot, which generates approximately 500 µm depth columns, but does not penetrate the dermis, only reaching approximately 1 spot/mm2 . The proportion of macrophage clusters significantly increased upon irradiation, whereas the proportion of fibroblast clusters decreased. The macrophages strongly expressed C-C chemokine receptor type 2 (Ccr2), which is known to be a key signal for injury-induced hair growth. CONCLUSIONS: We found that fractional CO2 laser irradiation recruited Ccr2 positive macrophages, and induced hair regrowth in a mouse alopecia model. These findings may contribute to the development of stable and effective fractional laser irradiation conditions for human alopecia treatment.


Assuntos
Dióxido de Carbono , Lasers de Gás , Alopecia/genética , Alopecia/radioterapia , Animais , Dióxido de Carbono/farmacologia , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Cabelo , Humanos , Lasers de Gás/uso terapêutico , Camundongos
17.
Phys Med ; 98: 45-52, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35490529

RESUMO

PURPOSE: To evaluate the displacement of gross tumor volume (GTV) positions caused by intrafractional residual setup errors (RSEs) and to accumulate delivered dose distributions considering intrafraction RSEs in fractionated-stereotactic radiotherapy (f-SRT) with single isocenter volumetric modulated arc therapy (SI-VMAT) for multiple brain metastases. METHODS: Overall, 72 consecutive patients who underwent f-SRT with SI-VMAT for multiple brain metastases were included. For all patients, 6D correction was performed using the ExacTrac X-ray (ETX) system. GTV displacement (ΔD) was calculated considering the intrafractional RSEs measured by the ETX system during irradiation. The correlation between ΔD and the distance from the isocenter to each GTV (d) was analyzed. Computed tomography (CT) images considering the intrafractional RSEs were generated for five patients with ΔD > 1 mm. The delivered dose distributions for all fractions were reconstructed on the corresponding CT, followed by their accumulation. RESULTS: The 95th percentile of ΔD from 7,270 resultant center positions of 417 GTVs was 0.92 mm. No correlation was observed between ΔD and d. For 53 GTVs from five patients with ΔD > 1 mm, the difference of GTV D99.5% and D0.5% between the planned and accumulated values was -0.4 ± 2.5% and -1.0 ± 0.8%, respectively. There was no correlation between d and the difference of GTV D99.5% and D0.5%. CONCLUSIONS: We found no significant difference in GTV D99.5% and D0.5%, despite the location of GTVs far from the isocenter. However, it should be noted that this result was because the intrafractional RSEs were reduced to a clinically acceptable level.


Assuntos
Neoplasias Encefálicas , Radiocirurgia , Radioterapia de Intensidade Modulada , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Progressão da Doença , Humanos , Radiocirurgia/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos
18.
Cell Mol Life Sci ; 79(2): 109, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-35098363

RESUMO

Duchenne muscular dystrophy (DMD), the most severe form of dystrophinopathies, is a fatal X-linked recessive neuromuscular disorder characterized by progressive muscle degeneration and various extents of intellectual disabilities. Physiological and pathological roles of the responsible gene, dystrophin, in the brain remain elusive due to the presence of multiple dystrophin products, mainly full-length dystrophin, Dp427, and the short product, Dp71. In this study, we generated a Dp71-specific hemagglutinin (HA) peptide tag-insertion mice to enable specific detection of intrinsic Dp71 expression by anti-HA-tag antibodies. Immunohistochemical detections in the transgenic mice demonstrated Dp71 expression not only at the blood-brain barrier, where astrocytic endfeet surround the microvessels, but also at the inhibitory postsynapse of hippocampal dentate granule neurons. Interestingly, hippocampal cornu ammonis (CA)1 pyramidal neurons were negative for Dp71, although Dp427 detected by anti-dystrophin antibody was clearly present at the inhibitory postsynapse, suggesting cell-type dependent dystrophin expressions. Precise examination using the primary hippocampal culture validated exclusive localization of Dp71 at the inhibitory postsynaptic compartment but not at the excitatory synapse in neurons. We further performed interactome analysis and found that Dp71 formed distinct molecular complexes, i.e. synapse-associated Dp71 interacted with dystroglycan (Dg) and dystrobrevinß (Dtnb), whereas glia-associated Dp71 did with Dg and dystrobrevinα (Dtna). Thus, our data indicate that Dp71 and its binding partners are relevant to the inhibitory postsynaptic function of hippocampal granule neurons and the novel Dp71-transgenic mouse provides a valuable tool to understand precise physiological expressions and functions of Dp71 and its interaction proteins in vivo and in vitro.


Assuntos
Distroglicanas/metabolismo , Proteínas Associadas à Distrofina/metabolismo , Distrofina/metabolismo , Neuroglia/metabolismo , Neuropeptídeos/metabolismo , Sinapses/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Células Cultivadas , Distroglicanas/genética , Distrofina/genética , Proteínas Associadas à Distrofina/genética , Células HEK293 , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Camundongos Transgênicos , Microscopia Confocal , Neurônios/metabolismo , Neuropeptídeos/genética , Ligação Proteica
19.
Acta Histochem Cytochem ; 55(6): 193-202, 2022 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-36688137

RESUMO

Bisphenol A (BPA) is an endocrine disrupting chemical. Human epidemiological studies have suggested that adverse neurobehavioral outcomes are induced by fetal exposure to BPA. The remarkable differences in the corticogenesis between human and agyrencephalic mammals are an increase in the intermediate progenitor cells (IPCs) and a following increase in the subplate thickness. It is uncertain whether low doses of BPA (low-BPA) affect human early corticogenesis when basal progenitor cells (BPs) produce IPCs resulting in amplified neurogenesis. In this study, human-derived neuronal stem/progenitor cells were exposed to low-BPA or the vehicle only, and the resultant cell type-specific molecular changes and morphology were analyzed. We focused on stem cells immunoreactive for SOX2, BPs for NHLH1, and immature neurons for DCX. SOX2-positive cells significantly decreased at day in vitro (DIV) 4 and 7, whereas NHLH1-positive cells tended to be higher, while DCX-positive cells significantly increased at DIV7 when exposed to 100 nM of BPA compared with the vehicle. Morphologically DCX-positive cells showed a decrease in unipolar cells and an increase in multipolar cells when exposed to 100 nM of BPA compared with the vehicle. These results provide insights into the in vivo effect of low-BPA on neuronal differentiation in the human fetal corticogenesis.

20.
Radiat Oncol ; 16(1): 49, 2021 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-33676532

RESUMO

BACKGROUND: This study aimed to quantify errors by using a cine electronic portal imaging device (cine EPID) during deep inspiration breath-hold (DIBH) for left-sided breast cancer and to estimate the planning target volume (PTV) by variance component analysis. METHODS: This study included 25 consecutive left-sided breast cancer patients treated with whole-breast irradiation (WBI) using DIBH. Breath-holding was performed while monitoring abdominal anterior-posterior (AP) motion using the Real-time Position Management (RPM) system. Cine EPID was used to evaluate the chest wall displacements in patients. Cine EPID images of the patients (309,609 frames) were analyzed to detect the edges of the chest wall using a Canny filter. The errors that occurred during DIBH included differences between the chest wall position detected by digitally reconstructed radiographs and that of all cine EPID images. The inter-patient, inter-fraction, and intra-fractional standard deviations (SDs) in the DIBH were calculated, and the PTV margin was estimated by variance component analysis. RESULTS: The median patient age was 55 (35-79) years, and the mean irradiation time was 20.4 ± 1.7 s. The abdominal AP motion was 1.36 ± 0.94 (0.14-5.28) mm. The overall mean of the errors was 0.30 mm (95% confidence interval: - 0.05-0.65). The inter-patient, inter-fraction, and intra-fractional SDs in the DIBH were 0.82 mm, 1.19 mm, and 1.63 mm, respectively, and the PTV margin was calculated as 3.59 mm. CONCLUSIONS: Errors during DIBH for breast radiotherapy were monitored using EPID images and appropriate PTV margins were estimated by variance component analysis.


Assuntos
Suspensão da Respiração , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Neoplasias Unilaterais da Mama/radioterapia , Adulto , Idoso , Análise de Variância , Feminino , Humanos , Pessoa de Meia-Idade , Movimento (Física) , Dosagem Radioterapêutica , Erros de Configuração em Radioterapia/prevenção & controle , Tomografia Computadorizada por Raios X , Neoplasias Unilaterais da Mama/diagnóstico por imagem , Neoplasias Unilaterais da Mama/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...